# All Questions

8 questions
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### Why do we observe two separate rings for signal and idler in type-II non-collinear SPDC (Spontaneous Parametric Down Conversion) Process?

I understand that in SPDC process (here: type-I, non-collinear), there is conservation between the pump, signal and idler photons in terms of energy and momentum, as a result of which the signal and ...
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### Order of magnitude radiation measures conversion?

Standard unit of ionizing radiation dose is Sievert. I can get a rough idea of how dangerous absorbing various amounts is from https://xkcd.com/radiation/ and other sources. There are many other ...
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### Does freezing point depression also affect the speed at which something melts?

If you have a pure water frozen, then it should begin to melt if you apply 33°F air to it. If you have impure water that's frozen, it's melting temperature might have dropped to 30°F. If you apply ...